Image display method and method for performing radiography of image

ABSTRACT

CT images are interpreted while being displayed in order (STEP S 16 ), and when a CT image is observed in which the presence of a lesion is suspected, an “Add Marker” button is clicked to add a marker to that CT image (STEPS S 18 , S 20 ). By means of the click operation, a marker is automatically added at a slice position on a scanogram that corresponds to the CT image (CT image requiring precise examination) in which the presence of a lesion is suspected. By automatically adding a marker at a desired slice position on a scanogram in this manner, it is possible to set scanning conditions for the purpose of a precise examination while viewing the marker on the scanogram (STEP S 24 ). It is thus possible to accurately set a range for precise examination by a simple operation in a short time.

TECHNICAL FIELD

The present invention relates to a method for displaying images and amethod for performing radiography of image, and more particularly to amethod for displaying images and a method for performing radiography ofimage that can simply carry out instructions concerning a tomogram of asubject in doing a precise examination or rescan.

BACKGROUND ART

(1) Method of Setting a Range for Precise Examination in CT (ComputedTomography) Examination

In a CT examination, a scanogram is taken first, and slice positions anda range are subsequently determined based on the scanogram before takingCT images. Next, screening (assessment of the presence or absence of alesion) is performed using the CT images to perform a preciseexamination. Hereinbelow, the term “precise examination” refers to anexamination that is performed in a CT examination with the purpose ofobserving a lesion when the presence of a lesion is suspected based onthe results of screening.

When performing a precise examination, imaging conditions are set toobtain more detailed and clearer CT images than images obtained byscreening, and then CT images are taken again. In an example ofexamining lung, images are taken for screening by employing a slicethickness of 10 mm and a table speed of 10 mm, while in a preciseexamination images of only a region where existence of lesion issuspected in the screening are produced again by employing a slicethickness of 2 mm and a table speed of 2 mm.

Although in screening an imaging range is generally set to cover all theorgans, in a precise examination only a region where existence of alesion is suspected is usually set as an object of imaging. This isbecause taking an image again in a precise examination of a region wherea lesion is not observed in screening would constitute unnecessaryradiation exposure. Accordingly, the range of imaging in a preciseexamination is determined on the basis of the slice position of the CTimages obtained by screening.

When setting the scanning conditions for a conventional preciseexamination, based on the results of observation of CT images obtainedin screening (FIGS. 11(1) and 11(2)), the operator transcribes the slicepositions of the CT images where existence of a lesion is suspected intoa memo pad (FIG. 11(3)) (depending on the sizes or number of lesions, aplurality of slice positions may be transcribed). Then, as shown in FIG.12, the operator sets the slice positions while looking at the slicepositions written in the memo pad. Since the slice positions are writtenwith 5 digits or more, such as 1234.5 mm, it is difficult to rememberthe slice position mentally, and therefore many operators transcribe thepositions into a memo pad.

Most current X-ray CT apparatuses employ a GUI (Graphical UserInterface). Therefore, when observing images many operators hold a“mouse” in their dominant hand (the right hand in many cases). However,in order to transcribe a slice position into a memo pad, the operatormust release the mouse from their dominant hand to hold a pen and writedown the slice position in the memo pad. Then, when observing thescreening images again, the operator must put down the pen and hold themouse again. Thus, there is a problem that in order to record a rangefor a precise examination in a memo pad, an operator must switch holdinga mouse over to holding a pen several times.

Further, in screening, a mistake may occur when a operator transcribes aslice position of CT image where existence of a lesion is suspected intoa memo pad. There is also a possibility of a mistake occurring whensetting slice positions for a precise examination based on the figureswritten into the memo pad.

Furthermore, in the conventional method using a memo pad, due to thecomplexity of the operations, a substantial time is required to set thescan conditions for changing from screening to precise examination.During the time period taken to change from screening to preciseexamination, the subject to be examined is not allowed to move from thetable to avoid inconformity of slice positions between screening andprecise examination, whereby the time for setting the scan conditions ofthe precise examination is weariness for the subject.

(2) Method of Setting a Slice Position for Rescanning in CT Examination

When an artifact appears in a specific CT image owing to a certaincause, such as movement of the subject, in a conventional technique, theoperator first records the slice position of the CT image in which theartifact appears in a memo pad. Thereafter, the operator sets the sliceposition to be re-scanned while looking at the slice position written inthe memo pad. In a similar manner to the above method (1), the operatormust switch holding a mouse over to holding a pen several times in orderto record the slice position to be re-scanned in the memo pad. There isa problem that recording these slice positions in a memo pad during theexamination that requires speed is troublesome and complicated.

There also is a possibility that a mistake will be made whentranscribing the positions of re-scanning in a memo pad or when settingthe positions for rescanning based on the transcribed positions.Furthermore, for the same reasons as in the above (1), the operationsinvolved in setting the slice positions of re-scanning require a lengthytime period and make the subject wearied.

(3) Method for Marking an Image to be an Important Factor in Diagnosisand a Method for Displaying the Image with the Marker in CRT Diagnosis

The term “CRT diagnosis” refers to displaying an image on a CRT (CathodeRay Tube) to perform diagnosis without developing the image on film. InCRT diagnosis, an observer adds remarks to several CT images havingclincher for diagnosis among a series of images, and stores the imagesand remarks as electronic data. When adding the remarks, text data areused as a means of adding character information, and ROI (Region ofInterest), distance measurement, angle measurement, straight lines,curved lines, arrows and the like are used as a means for addinggraphical information.

When the stored electronic data of the stored series of images andremarks are read out again, CT images to which no remark is attached aredisplayed as they are, and CT images to which the remark is attached aredisplayed together with the character information and/or graphicalinformation.

Attaching the text data, ROI, distance measurement, angle measurement,straight line, curved line, arrow or the like to the CT image, sufficeit to say that play the role of “adding a marker (remark) to a CTimage”. However, while the function that adds these kinds of characterinformation and graphical information is to indicate and measure alesion visualized in a CT image, it is not a function of indicating theCT image of diagnostic importance itself.

In CRT diagnosis, there are cases where it is more appropriate that anobserver adds neither character information nor graphical information toa lesion visualized on several CT images having diagnostic clincheramong a series of CT images. For example, when observing a state that atumor is stained by a contrast medium according; to a lapse of time, orwhen observing a state where a tumor is gradually becoming small as aresult of periodic observation or the like, observation is facilitatedwhen superfluous characters or graphics are not displayed on the CTimage.

In this case, rather than adding a marker to the lesion on the CT image,it is more appropriate to add a marker to the CT images of diagnosticimportance. However, that type of method has not existed up to now.Therefore, when observing a state that a tumor is stained by a contrastmedium according to a lapse of time in the conventional method, theobserver observes CT images that are seemingly considered to be of thesame slice position, whereby there is a problem that the method lackscertitude. Furthermore, when stored electronic data for a series ofimages and remarks are read out again, CT images to which the remark isnot attached are displayed as they are, and CT images to which theremark is attached are displayed together with the character informationand/or graphical information.

When adding a marker to a CT image in the conventional method, textdata, ROI, distance measurement, angle measurement, straight line,curved line, arrow or the like is used as the marker. Because keyboardoperation or mouse operation involving several steps is respectivelyrequired to add the marker, these are not suitable for the purpose ofadding the marker to the CT image itself.

Furthermore, when a series of image data is readout that includes a CTimage to which a remark was added, in order to display the CT imagehaving the remark out of the plurality of images, it is necessary for anoperator to check images one by one starting from the first image tolocate the image with the remark in it. It has thus been necessary tocarry out image update operations several times until the CT image withthe remark in it is displayed. Furthermore, when there is a plurality ofCT images of diagnostic importance, there has been a drawback that aposition where the images with the remark in it (images of diagnosticimportance) is unknown until all the images are displayed at once.

(4) Method of Adding Markers to Images of Diagnostic Importance andFilming the Images (Printing the Images on Photographic Film) in CTExamination

In a similar manner to CRT diagnosis, in diagnosis using film anobserver adds remarks to several CT images having clincher in diagnosisout of a series of film. When viewing the film to diagnose, particularattention is paid to CT images to which the observer has added remarksamong the series of CT images.

In a conventional technique, in the same manner as in the CRT diagnosisof the above (3), text data, ROI, distance measurement, anglemeasurement, straight line, curved line, arrow or the like is also addedto the CT images for filming.

In a conventional technique, no method of adding a marker to the CTimage having diagnostic clincher exists other than adding a remark to aCT image on film.

Further, in the conventional technique, when explaining a treatment areaor an examination area to a subject, because the difference betweenabnormality and normality is not known by the average subject, it hasbeen necessary for a physician to write directly on a frame of film orto attach a piece of paper or the like. However, it is not preferablefrom the viewpoint of maintaining the medical information to afterwardprocess the film.

With respect to filming, as in the above (3), when adding a marker to aCT image, text data, ROI, distance measurement, angle measurement,straight line, curved line, arrow or the like is used as the marker asin the above (3) since keyboard operations or mouse operations involvingseveral steps are respectively required for each type of the marker,these types are not suitable for the purpose of adding a marker to a CTimage itself.

The present invention is provided in view of the foregoing, and it is anobject of the invention to provide a method for displaying images and amethod for performing radiography of image that make it possible toaccurately set of a range for precise examination and slice positionsfor rescanning in a short time by a simple operation.

Another object of the present invention is to provide a method fordisplaying images that easily displays a tomogram of an important factorfor diagnosis certainly at the same tomographic position, or for filmingas such.

DISCLOSURE OF THE INVENTION

In order to achieve the above objects, the present invention provides amethod for displaying images that displays a scanogram used fordetermining a scanning range of a subject to perform radiography toobtain tomograms and also displays tomograms of a plurality of slicepositions within a scanning range determined using the scanogram,comprising steps of: sequentially displaying the plurality of tomogramsto interpret the tomograms, designating tomograms for preciseexamination or rescanning while interpreting the displayed tomograms,and adding a marker at slice positions on the scanogram corresponding tothe designated tomograms.

According to the present invention, a scanogram and tomograms aredisplayed for screening. The scanogram and tomograms may be displayed ona screen at the same time, or may be displayed separately by switchingscreens. The tomograms are then interpreted while being sequentiallydisplayed, and when a tomogram having a susupect lesion on it or atomogram having an artifact on it is observed, an instruction is givento add a marker to the tomogram in question. For example, the observermay click an “Add Marker” button. By this input of an instruction, amarker is automatically added to the slice position on the scanogramcorresponding to the designated tomogram. A marker may also be added tothe designated tomogram itself. By automatically adding a marker at apredetermined slice position on a scanogram in this manner, a range fora precise examination or slice positions for rescanning can be set whileviewing the marker on the scanogram.

Preferably, positional information indicating the slice position isadded together with the marker for the slice position added to thescanogram. Therefore, it is no longer necessary to write positionalinformation indicating the slice position into a memo pad.

Preferably, positional information indicating the slice position of thedesignated tomogram is stored in a storage device.

To achieve the aforementioned objects, the present invention comprisessteps of performing radiography at a first slice thickness to obtain aplurality of tomograms from a predetermined scanning range of a subject,displaying in order the imaged plurality of tomograms to interpret thetomograms, designating tomograms for precise examination whileinterpreting the displayed tomograms, automatically setting a range forprecise examination within the predetermined slice range based on slicepositions of the designated tomograms, and performing imaging of theautomatically set range for precise examination at a second slicethickness that thinner than the first slice thickness.

Although an operator may set the range for precise examination manuallyon the basis of markers added to a scanogram, according to the presentinvention a range for precise examination is automatically set on thebasis of instructions input of a tomogram subject to preciseexamination, and imaging is automatically carried out using that rangeas the scanning conditions for the precise examination.

Preferably, the method further comprises a step of taking a scanogram ofthe subject in order to determine the predetermined scanning range.

Preferably, the step of designating tomograms to be subject to preciseexamination designates two tomograms as the first and last tomogram ofprecise examination, and the step of automatically setting the range forprecise examination sets the region between the slice positions of thetwo tomograms as the precise examination range. Alternatively, the stepof designating tomograms to be subject to precise examination designatesone tomogram to be subject to precise examination, and the step ofautomatically setting the range for precise examination sets apredetermined range that includes the one tomogram and tomograms priorto and after the one tomogram as the precise examination range. Asanother alternative, the step of designating tomograms to be subject toprecise examination designates a plurality of tomograms to be subject toprecise examination, and the step of automatically setting the range forprecise examination sets a range that covers the plurality of tomogramsas the precise examination range.

To achieve the aforementioned objects, the present invention furtherprovides a method for displaying images that displays a scanogram usedfor determining a slice range or slice positions of a subject to performradiography to obtain tomograms, and also displays tomograms of aplurality of slice positions taken within a slice range that isdetermined using the scanogram, comprising steps of: sequentiallydisplaying the plurality of tomograms to interpret the tomograms,designating tomograms as important factors in diagnosis whileinterpreting the displayed tomograms, and adding a first marker at slicepositions on the scanogram that correspond to the designated tomograms.

According to the present invention, when a tomogram is designated as animportant factor for diagnosis while interpreting tomograms sequentiallydisplayed, a first marker is added at the slice position on thescanogram corresponding to the designated tomogram.

Preferably, the method further comprises a step of displaying thetomogram at a slice position of one of the first markers when the one isarbitrarily designated out of the first markers on the scanogram. Morespecifically, when an arbitrarily designated first marker is on thescanogram at the time of another interpretation, the tomogram (tomogramof diagnostic importance) for the slice position indicated by thedesignated first marker is displayed. This step is advantageous whendiagnosis is performed by a plurality of interpreters.

Preferably, a second marker is added to the designated tomogram toindicate including an important factor for diagnosis.

Preferably, the method has a step of printing a scanogram on which thefirst marker is added and a view of tomograms to which the second markeris added on film. Accordingly, tomograms of diagnostic importance andthe slice positions for those tomograms on a scanogram can be apparentlyseen in images printed on the film.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a hardware configuration of anX-ray CT apparatus to which a method for displaying images and a methodfor imaging of the present invention are applied;

FIG. 2 is a flowchart illustrating an embodiment of procedures forsetting a range for precise examination according to the presentinvention;

FIG. 3 is a view used to describe operations performed to add a markerto a CT image having a suspect lesion;

FIG. 4 is a view illustrating a method of setting a range for preciseexamination while viewing positional information and markers on ascanogram;

FIG. 5 is a flowchart illustrating an embodiment of procedures forsetting re-scanning slice positions according to the present invention;

FIG. 6 is a view used to describe operations of adding a marker to a CTimage to be re-scanned;

FIG. 7 is a flowchart illustrating a method of adding a marker to animage of diagnostic importance;

FIG. 8 is a flowchart illustrating a method of filming or re-displayingan image of diagnostic importance to which a marker was added;

FIG. 9 is a view used to describe a method of displaying a CT image ofdiagnostic importance;

FIG. 10 is a view showing a film to which images including CT images ofdiagnostic importance printed;

FIG. 11 is a view used to describe a conventional method of observing CTimages obtained in screening and transcribing a range for preciseexamination into a memo pad; and

FIG. 12 is a view used to describe a conventional method of setting arange for precise examination from numbers written into a memo pad.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinbelow, preferred embodiments of a method for displaying images anda method for performing radiography of image according to the presentinvention are described in reference of the attached drawings.

FIG. 1 is a schematic diagram showing a hardware configuration of anX-ray CT apparatus to which the method for displaying images and methodfor performing radiography of image according to the present inventionare applied.

As shown in FIG. 1, the X-ray CT apparatus includes an X-ray tube 10, adetecting device 12, a table 14, an image processing unit 16 and anoperator console 18.

The X-ray tube 10 and the detecting device 12 are disposed so as to faceeach other, and when taking a tomogram (CT image) they revolve aroundthe circumference of the table 14 on which a subject is positioned.X-rays radiated from the X-ray tube 10 penetrate through the subject andthe table, and are detected by the detecting device 12. Signals detectedby the detecting device 12 is subject to pre-processing and imageconfiguration processing in the image processing unit 16 to create a CTimage.

CT images created in this manner are displayed on a CRT monitor in theoperator console 18 and are also stored as image data in a storagedevice 20 in the operator console 18.

The method for displaying images of the present invention is not limitedto an X-ray CT apparatus that performs CT imaging and displays theobtained CT images or scanogram, and the method can also be applied toan image display apparatus that has a function for displaying CT images.

More specifically, an image display apparatus is an apparatus includingonly the operator console 18 part of the X-ray CT apparatus. While anX-ray CT apparatus stores image data created by the image processingunit 16 in the storage device 20 of the operator console 18, an imagedisplay apparatus stores image data in the storage device 20 of theoperator console 18 via a network or storage medium. The display ofimages, distance measurement of lesions displayed on an image, input ofcomments and the like can be performed using the operator console 18,and these types of added data can be stored together with the imagedata.

In recent years, there has been an increase in the number of hospitalsthat carry out so-called CRT diagnosis, in which images are not printedonto film but are stored as electronic data to observe the images on animage display apparatus. An image display apparatus is used in varioussituations in such hospitals, for example, when a physician interpretingthe images adds a comment thereto, when a physician is deliveringdiagnosis, when a physician is explaining the condition of a disease toa subject, or when past images are compared with current images.

Next, embodiments of the method for displaying images and method forperforming radiography of image of the present invention will bedescribed.

(1) Method for Setting Range of Precise Examination in CT Examination

FIG. 2 is a flowchart showing an embodiment of the procedures forsetting the range of a precise examination according to the presentinvention.

<STEP S10>

A screening image is taken for positioning use for the purpose ofperforming screening.

As shown in FIG. 3(1), a scanogram is an X-ray image that issequentially taken first to accurately perform radiography for the rangeof an organ of interest. A scanogram is created by radiating X-rayswhile moving only the table 14 on which the subject is positioned,without rotating the X-ray tube 10 and the detecting device 12.

<STEP S12>

On the scanogram obtained in the preceding step, the slice positions andrange of images for screening are set. This setting can be performed byinputting figures that indicate the slice positions or range using akeyboard or by designating slice positions using a mouse.

<STEP S14>

CT imaging is performed for the slice positions and range set in thepreceding step. CT imaging is performed by rotating the X-ray tube 10and detecting device 12 and radiating X-rays. Two patterns may beemployed for the CT imaging: one is an imaging pattern in which X-rayradiation and table movement are repeated alternatively, and the secondis an imaging pattern in which the table 14 is moved continuously whileX-rays are continuously radiated thereto.

<STEP S16>

The thus-obtained CT images and scanogram are observed (interpreted)(FIG. 3(1)).

<STEP S18>.

After interpreting the CT images, judgment is made as to whether thereis the suspicion of a lesion (i.e., whether or not a precise examinationis necessary).

<STEP S20>

When a precise examination is necessary, the operator clicks on an “AddMarker” button (for example, a software button displayed on the monitor)using the mouse (FIG. 3(2)). If a precise examination is not required,the operation jumps to STEP S22.

When the “Add Marker” button is clicked, a marker is added to the CTimage and a marker and slice position information are added to thescanogram (FIG. 3(3)). Further, the slice position of the CT image thatwas clicked is stored in the storage device 20 or the like.

<STEP S22>

Judgment is made as to whether all the CT images have been interpretedor not. If all the images have not been interpreted, the CT images areadvanced by one frame and the process from STEP S16 to STEP S20 isrepeated.

<STEP S24>

The setting of scan conditions for the purpose of precise examination isperformed. As shown in FIG. 4, the slice positions are set while viewingthe markers and positional information on the scanogram. Morespecifically, since slice positions and numerical values for CT imagesin which a lesion is suspected to be present are displayed on thescanogram, the range for the precise examination is set manually basedon the scanogram.

<STEP S26>

CT imaging is performed for the purpose of precise examination withrespect to the set range for precise examination. CT imaging for thepurpose of precise examination is performed after setting the imagingconditions (slice thickness and table speed) so as to obtain CT imagesthat are more detailed and clearer in comparison to images obtained inCT imaging for the purpose of screening.

Although in the present embodiment a case has been described in which arange for precise examination is set manually on the basis of markersand slice position information displayed on a scanogram, the presentinvention is not limited thereto, and imaging may be carried outautomatically by checking off CT images where a lesion is suspected tobe present to automatically set a range for precise examination andperform radiography employing that range as the scan conditions for theprecise examination.

Automatic setting of the precise examination range may be performed by amethod in which two CT images that correspond to the first and lastslice positions of the precise examination are checked off, a method inwhich one CT image is checked off and a predetermined range includingthat CT image and CT images prior to and after that CT image is set asthe precise examination range, or a method in which, when a plurality ofCT images have been checked off, a range that covers all of the checkedoff CT images is set as the range for precise examination. Further, whenautomatically setting a precise examination range, the display ofmarkers or slice positions on the scanogram can be omitted.

(2) Method of Setting Slice Positions for Rescanning in CT Examination

When performing a CT examination, sometimes an artifact appears in onlythe CT image for a specific slice position due to some cause, such asmovement by the subject during imaging. When this happens, imaging isperformed again for only the same position as that of the CT image inwhich the artifact appeared. This type of imaging is referred to as“rescanning”.

FIG. 5 is a flowchart showing an embodiment of the procedures forsetting slice positions for rescanning according to the presentinvention. The steps therein that are common with the flowchart shown inFIG. 2 have been given the same step number, and a detailed descriptionof these steps is omitted.

The flowchart shown in FIG. 5 differs from the flowchart shown in FIG. 2in that in place of STEP S18, STEP S24 and STEP S26 in FIG. 2, theprocesses of STEP S30 and STEP S32 are carried out.

<STEP S30>

A CT image is interpreted (FIG. 6(1)), and the operator assesses whetherthe CT image is one in which an artifact has been generated due tomovement by the subject (i.e., whether or not a rescan is necessary). Ifa rescan is necessary, the operator clicks on an “Add Marker” buttonusing a mouse (FIG. 6(2)). When the “Add Marker” button is clicked, amarker is added to the CT image and a marker and slice positioninformation is added to the scanogram (FIG. 6(3)).

<STEP S32>

CT imaging is performed for the purpose of rescanning. In this case,when a “Rescan Marked Position” button (for example, a software buttondisplayed on the monitor) is clicked using the mouse, rescanning isperformed for slice positions that have been added with a marker on thebasis of the slice positions of the CT images for which the “Add Marker”button has been clicked.

(3) Method for Adding Marker to Image as an Important Factor forDiagnosis in CRT Diagnosis

FIG. 7 is a flowchart illustrating a method of adding a marker to animage that will be an important factor in diagnosis.

<STEP S40>

A CT image and scanogram stored in the storage device 20 of the operatorconsole 18 are displayed on a monitor.

<STEP S42>

The displayed CT image is observed (interpreted).

<STEP S44>

Upon interpreting the CT image, judgment is made as to whether a CTimage that will be an important factor in diagnosis is displayed.

<STEP S46>

When a CT image that will be an important factor in diagnosis isdisplayed, the operator clicks on the “Add Marker” button with themouse. If the displayed CT image will not be an important factor indiagnosis the operation jumps to STEP S22.

When the “Add Marker” button is clicked, a marker is added to the CTimage and a marker and slice position information are added to thescanogram.

<STEP S48>

Judgment is made as to whether all the CT images have been interpreted,and if all the images have not been interpreted the CT images areadvanced by one frame and the above process from STEP S42 to STEP S46 isrepeated.

By the above operations, markers are added to images that will beimportant factors in diagnosis, and markers and slice positioninformation are added to the scanogram. The scanogram and CT images towhich these markers and so forth have been attached are stored in thestorage device 20.

(4) Method for Displaying Images Added with Markers as Important Factorsin Diagnosis and Method for Filming the Images (Printing the Images onFilm) in CT Examination

FIG. 8 is a flowchart illustrating a method for filming or re-displayingan image to which a marker was added as an important factor in diagnosisin the above manner.

<STEP S50>

In order to perform diagnosis or filming, a scanogram added with amarker is readout from the storage 20 and displayed on a monitor.

<STEP S52>

If diagnosis is being performed the operation proceeds to STEP S54, andwhen diagnosis is not being performed the operation jumps to STEP S60.

<STEP S54>

In order to deliver diagnosis, the marker on the scanogram is clickedusing the mouse (FIG. 9(1)).

<STEP S56>

The CT image for the slice position that corresponds to the marker onthe scanogram is readout from the storage device 20 and displayed on themonitor. Thus, a CT image that is an important factor in diagnosis canbe displayed by just one click.

<STEP S58>

Judgment is made as to whether or not to terminate diagnosis. To displayanother CT image attached with a marker on the scanogram, the operationreturns to STEP S54.

<STEP S60>

Judgment is made as to whether or not to perform filming of thescanogram and CT image(s).

<STEP S62>

When performing filming, if markers have been added to the scanogram andCT images, as shown in FIG. 10, the scanogram and CT images aresubjected to filming in the state where the markers are added thereto.

When delivering diagnosis, the observer can interpret the CT imageswhile paying particular attention to the images added with markers, andmay insert a comment with respect to a CT image attached with a marker.

INDUSTRIAL APPLICABILITY

As described in the foregoing, according to the present invention thesetting of a range for precise examination or slice positions forrescanning or the like can be performed accurately by a simple operation(for example, clicking a mouse) in a short time. It is thus possible toeliminate mistakes that occur when transcribing values for a range forprecise examination or the like in a memo pad and mistakes that occurwhen setting the range or the like. Further, the time that a subject isbound to the CT apparatus can also be shortened. Since the slicepositions can be handled as visual information in addition to numericalinformation, a range for precise examination or rescanning positions canbe set with greater accuracy.

Further, since a tomogram that is an important factor for diagnosis canbe displayed by simply designating a marker on a scanogram using a mouseor the like, for example, when diagnosis is delivered by a plurality ofinterpreters or the like, the second and subsequent interpreters caninterpret the tomogram with better efficiency. Further, the method ofadding a marker is extremely simple when compared with conventionalinput operations, such as text data, ROI, distance measurement, anglemeasurement, straight line, curved line, arrow and so forth, and sincethe method only involves adding a marker to the tomogram, there is nohindrance to observation of a lesion even in cases such as observing astate where a lesion is stained by a contrast medium over the course oftime. The effect of the invention is manifested more noticeably as thenumber of images being handled increases, and it is particularly suitedto observation of images that were taken using a multi-slice CTapparatus that generates a large quantity of images.

Furthermore, a tomogram that is an important factor for diagnosis can besimply found from among a plurality of tomograms on a film.

1. A method for displaying images that displays a scanogram used fordetermining a scanning range of a subject to perform radiography oftomograms and also displays tomograms of a plurality of slice positionsin a scanning range that is determined using the scanogram, comprisingthe steps of: sequentially displaying the plurality of tomograms tointerpret the tomograms; designating a tomogram for precise examinationor rescanning while interpreting the displayed tomograms; and adding amarker at a slice position on the scanogram corresponding to thedesignated tomogram.
 2. The method for displaying images according toclaim 1, wherein positional information that indicates the sliceposition is added together with the marker of the slice position addedon the scanogram.
 3. The method for displaying images according to claim1, wherein positional information that indicates a slice position of thedesignated tomogram is stored in a storage device.
 4. A method forperforming radiography of image, comprising the steps of: performingradiography at a first slice thickness to obtain a plurality oftomograms from a predetermined scanning range of a subject; sequentiallydisplaying the obtained plurality of tomograms to interpret thetomograms; designating tomograms to be subject to precise examinationwhile interpreting the displayed tomograms; automatically setting arange for precise examination within the predetermined scanning rangebased on slice positions of the designated tomograms; and performingradiography of the automatically set range for precise examination at asecond slice thickness that is thinner than the first slice thickness.5. The method for performing radiography of image according to claim 4,further comprising a step of performing radiography of a scanogram ofthe subject to determine the predetermined scanning range.
 6. The methodfor performing radiography of image according to claim 4, wherein thestep of designating tomograms to be subject to precise examinationdesignates two tomograms as a first and last tomogram of preciseexamination, and the step of automatically setting a range for preciseexamination sets a region between the slice positions of the twotomograms as a range for precise examination.
 7. The method forperforming radiography of image according to claim 4, wherein the stepof designating tomograms to be subject to precise examination designatesone tomogram to be subject to precise examination, and the step ofautomatically setting a range for precise examination sets apredetermined range that includes the one tomogram and tomograms priorto and after the one tomogram as a range for precise examination.
 8. Themethod for imaging according to claim 4, wherein the step of designatingtomograms to be subject to precise examination designates a plurality oftomograms to be subject to precise examination, and the step ofautomatically setting a range for precise examination sets a range thatcovers the plurality of tomograms as a range for precise examination. 9.A method for displaying images that displays a scanogram used fordetermining a slice range or slice positions of a subject to performradiography of tomograms, and also displays tomograms of a plurality ofslice positions taken within a slice range determined using thescanogram, comprising the steps of: sequentially displaying theplurality of tomograms to interpret the tomograms; designating atomogram as an important factor for diagnosis while interpreting thedisplayed tomograms; and adding a first marker at a slice position onthe scanogram corresponding to the designated tomogram.
 10. The methodfor displaying images according to claim 9, further comprising a step ofdisplaying the designated tomogram of the slice position indicated bythe first marker when an optional first marker is designated on thescanogram to which the first marker was added.
 11. The method fordisplaying images according to claim 9, wherein a second marker is addedon the designated tomogram to indicate including an important factor fordiagnosis.
 12. The method for displaying images according to claim 11,further comprising a step of printing on a film a scanogram on which thefirst marker was added and a view of tomograms that contains tomogramsto which the second marker was added.